Spark plug



Patented ca. 13, 192s.

A UNITED STATES-PATENT oFnce. v

:rosnrn a. saw, or uonon'ennntn, PENNSYLVANIA.

SPARK PLUG.

- Application filed August 10, 1828. Serial No. 656,825.

of the invention are to provide a spark plug having means whereby multiple sparks will be provided for quickly and effectively igniting the explosive charge; which'provides a novel and improved device for securing the main'insulating' core within the metal shell;

' which permits of the convenient regulation of the spark gap relationship between the various electrodes; which provides for the adjustment of the spark permitting of its efiicient use in connection with anterior grades of fuel and which embodies novel means for priming the engine.

It is also within the scope of the invention to provide a spark plug having the imparts hereinafter described and proved features above noted and. which at the same time is comparatlvely simple in its.

construction and arrangement dura 1e, compact and inexpensive. to manufacture as well as being thoroughly practical, reliable and eflicient'in use. 7

With the foregoing and other objects in view which will ap ar as the description proceeds the invention resides in the construction, combination and arrangement of illustrated in the accompanying drawing wherein is shown an embodiment'of the invention, it

being understood that changes in the precise embodiment of the invention herein dis closed,- can be made within the scope of what is claimed without departing from the spirit of the invention.

vIn the drawing forming a portion of this specification and wherein like numerals of. reference designate corresponding parts throughout the several views Figure 1 is a side view partially in section of a spark plug constructed in accordance with my invention.

Figure 2 is an enlarged detail side view of the tubular electrode, and Figure 3 is a perspective view of the annular electrode associated therewith.

Figure 4' is an enlarged section of the metal collar '4. The latter if fornie with a depending annular flange 5 which is forced into the annular recess 6, formed in the upper portion of the main core 1, during the assembly of the spark plug.

The lower portion of the main core'l is substantially cone-shaped and is formed with a continuous spiral groove 7 while the upper portion of the core 1 is formed to provide an annular flange 8, for the purposes to be described.

The shell 3 is provided'with a horizontally disposed aperture 9, the inner portion of which is reduced and formed to provide a seat which is associated with the corres onding inner end of the bolt 10. The atter threadably engages the enlarged portion of the a erture 9.and.is formed with a conduit 10' w ich terminates at its'inner end with a pair of reduced ports 9'. The aperture 9 and associated bolt 10 are provided to ermit of the priming of the engine c lin ers through the spark plugs. By slig tly releasing the bolt 10 in the aperture 9, the

priming medium may be injected into the.

shell 3 through the conduit 10' and ports '9'. The priming medium will enter the spiral groove 7, of the main core 1, and travel t erein downwardl toward the lower terminal of the main e ectrode 2. During such downward travel, the priming medium will vaporize, forming an explosive medium in annular grooves, providing annular projections 13 therebetween which are adapted to engage the cylinder head, or preferably the washers 14 if used between the cylinder head and the shell shoulder, for establishing a perfectly tight connection.

The shell 3 is provided with a contracted lower end 15. the inner wall of which is threaded. Threadably mounted in the threaded lower end 15, of the shell 3, is a bushing 16 in which an auxiliary core 17 is fixedly supported. Thecore 17 is formedwith a threaded central bore in which a tubular electrode 18 .is threadably mounted. The upper end of the tubular electrode 18 is aligned and coacts with the lower end of the electrode 2 and is provided with a plurality of vertically disposed slots 19 open at their upper ends. The lower end is also provided with a plurality of open slots 20, and is flared, as indicated at 21. The slots 19 and 20 are provided to prevent deterioration of the functioning ends of the tubular electrode 18 by establishing a plurality of firing ends which will not become inactive at the same time by pitting or other causes. An inner annular electrode 22 surrounds the lower end of the tubular electrode 18 and is supported from the lower end of the metal shell 3. The annular electrode 22 forms a spark gap at any point from the tubular electrode 18.

The lower portion of the shell 3 is provided with a plurality of large openings 23 I to allow the escape of the spark, formed between the adjacent ends of the electrodes 2 and 18, to the explosion chamber of the engine cylinder. The tubular electrode 18 with its flared lower end 21 also serves to facilitate to escape of the spark therethrough to vthe explosion chamber, and for.

this reason the passage opening through the tubular electrode. 18 is preferably tapered as clearly shown in Figure 2, of the drawing.

A metal cap 24 is fixed to the upper end of the main. core 1 by the engagement of its lower edge with the annular flange 8. A terminal binding post 25 is mounted on top of the cap 24. A pair of adjustable spark regulating screws 26 and 27 are threadably mounted in the cap 24. The screws 26 and 27 are preferably diametrically disposed relatively to each other,'but not essentially so. A pair of openings '28 are formed in the cap 24 and are disposed at right angles with respect to the screws 26 and 27, and are diametrically disposed with respect to each other. I A metal cap nut threadably engages the upper end of the main electrode 2 and c0- acts with the spark adjusting screws 26 and reserve nut 28 to produce a light or lean spark for use in connection with high grade light fuel, while the screw 27 is heavy and adapted to coact with the cap nut 28 to produce a fat spark adaptable for use in connection with inferior heavy grades of fuel. The openings 28, are formed in the cap 24, permit of the spark being seen when either of the screws 26 or 27 are being adjusted to the position required, or to ascertain whether the spark plug is functioning properly.

It will be noted that the construction of my improved spark plug will not only allow the regulation of the spark by the ready adjustment of the screws 26 and 27 as above described, but will permit also of the adjustment of the tubular electrode 18 in the auxiliary core'17, and the adjustment of the bushing 16 in the shell 3.

The modification illustrated in Figure 5,

of the drawing, comprises an auxiliary inv sulating core 29 adapted to be mounted in the bushing 16, of the preferred form, in stead of the core 17 and associated parts as described relative to the preferred form. The core 29 is provided with a central electrode 30 and a pair of secondary electrodes 31 and 32. The electrode 31 coacts with the electrode 30 and the electrode 32 coacts with the electrode 31 whereby a plurality of sparks are provided.

What I claim is 1. A spark plug comprising a main electrode, a peripherally threaded tubular electrode co-acting with, spaced from and arranged in lengthwise alignment with respect to the main electrode, an inner electrode associating with said tubular electrode, a pair of spaced cores of insulation, one of said cores carrying the main electrode and the outer of said cores having a threaded core through which extends the tubular electrode, the latter having threaded engagement with the wall of the bore, a metallic shell sup-- porting the core carrying ,the main electrode and carrying said inner electrode, and a bushing secured in the inner end of said shell and supporting said threaded core.

2. A spark plug comprising a main electrode, a peripherally threaded tubular electrode co-acting with, spaced from and arranged in length-wise alignment with'respect to the main electrode, an inner electrode associating with said tubular electrode, a

pair of spaced cores of insulation, one of said cores carrying the main electrode and the other of said cores having a threaded bore through which extends the tubular electrode, the latter having threaded engage-- ment with the wall of the bore, and means for supporting said cores and carrying said inner electrode, and said tubular electrode providedwith slitted flaring ends.

3. A spark plug comprising a main electrode, a peripherally threaded tubular electrode co-acting with, spaced from andarranged-in length-wise alignment with respectto the main electrode, an inner electrode associated with said tubular electrode, a pair of spaced cores of insulation, one of said cores carrying the main electrode and the outer of said-cores having a threaded bore through which extends the tubular electrode the latter having threaded engagement with the wall of the bore, a metallic shell supporting the corejcarrying the main electrode and carrying said inner electrode, and a bushing secured in the inner end of said shell and supporting said threaded core, and

said tubular electrode extending above and below said bushing andformed with slitted flaring ends.

4:. A plug comprising a metallic shell, a core of insulation clamped to and depending therein, a central electrode extended through said core, said 'shell having. a contracted inner end, a bushing secured to and projecting from said inner end, a tubular electrode aligning and coacting with and spaced from said central electrode, a core of insulation carried by said bushing and having the central electrode extended therethrough, and threadably engaging therewith, and. an inner electrode projected inwardly from said shell andv co-acting with the tubular electrode.

5. A plug comprising a metallic shell, a'

core of insulation clamped to and depending I therein, a central electrode extended through said core, said shell having a contracted inner end, a bushing secured to and projecting from said inner end, a tubular electrode aligning and co-acting with and spaced end portions.

In testimony whereof I aflixmy signature.

JOSEPH aeavmx, 

